Printed on 31-05-2013 16:12:12
Publisher Arnoldo Mondadori – Mondadori’s Company Archive
Magazine…. Pc Week
Publication Date…. 01/28/1988
Publication Number…. 0002
Page Number…. 0009
Title …. VREVIEW OF LOCAL NETWORK SOFTWARE
Summary…. Microsoft and Novell are the landmarks, from which LAN software is chosen
Author …. Roberto Mazzoni
Creation Date…. 03/22/1988
Local Networks and Network Software :The essential differences of our two reference models Microsoft Ms Net and Novell NetWare.
Main Article Text
Network software is the crucial element that determines the performance of a LAN and its ability to integrate with the outside world. In this issue, we are presenting an overview of the main products and criteria for their selection. Unfortunately, as often happens in the world of computers, the evolution of operational network systems is a story of standards, fighting and prevailing in a specific niche markets. In the world of personal computer networks there exist today, at least, two principal product families: the generation of packets centered on the specifics of Microsoft Ms Net and those, instead, that have protocols and file management systems whose details are specialized, amongst which is the noted Novell NetWare. The differences between these two worlds are quite precise and must be taken into consideration when choosing which operating system to install on one’s network. One should not underestimate the importance of software, taking into account technical characteristics of the interface data card and typological characteristics of the various systems. Let us examine the essential differences between the two models referred to earlier, for a better understanding, the Open model interconnect system of the International Organization for Standardization (ISO – OSI) is followed by all the local network designers. This model requires the division of network management on seven different levels, starting from the physical connection (level 1) finally arriving at the intrinsic application (layer 7). The importance cannot be understated since NetBios Ibm, was the first to bring a little order in this sector, presenting in 1985 the Pc Network and the Network Basic Input Output System. The NetBios provides the functions of the three intermediate layers of the OSI model : Sessions (level 5),transport layer (layer 4) , network layer (layer 3). For all intents and purposes, this software module manages the logical connection between two work stations in such a way that the messages sent by any user arrives at the destination node. As the data to be transmitted passes through the suitable processing provided by these three levels,control information is added So the package that travels on the cable does not only contain raw data, but also information about its destination. AS an intermediary , the NetBios acts as a fulcrum for the network and is a standard that all manufacturers have adopted, each providing software routines that emulate the functions of the original IBM product. NetBios is the meeting point between the worlds of IBM Microsoft and Novell. The differences between the various network standards are pronounced in the lower levels of the OSI model, where the physical connection (level 1) is handled,and the layer involving data connection (layer 2) , in addition to the upper ones, namely the presentation layer (level 6) and application layer (Level 7) . Examining connectivity of the physical controls are beyond the scope of this service, as it expressly refers to a variety of interface cards,the types of and transmission protocols (Ethernet, Token -ring, ArcNet, etc.) . Importance in determining the choice of software, are the highest levels, ie, those that bring NetBios into connection with the actual application program itself. To this end, Microsoft makes use of an interface called Redirector which is incorporated into its product Ms Net used by third parties for the development of network operating systems, while Novell bypasses Dos by directly administering the hardware resources of the server. The standard Microsoft’s, The Redirector, as the name suggests, works metaphorically as an exchange. When the user asks to store a file on the remote network server, the Redirector intercepts the request and prevents it arrival at the local Bios, or rather the routine software that handles the traffic which affects the single personal computer and any peripherals that are connected. The command is instead diverted to the NetBios making sure that it will reach its destination. All other lines of head commands must be received and interpreted by a Redirector module similar to what exists on the sender workstation. The jargon used,by the two modules to talk to each other, is known as, the Server Message Block (SMB),a protocol known otherwise as a core protocol. Any network based on the Microsoft Redirector adopts Smb while operating on NetBios, allows for remote file access, printer sharing and message handling. For the conversing with applications, the Redirector depends on the functions of Dos 3.1, with which it is tightly integrated. This version of Microsoft’s operating system provides an indispensable mechanism for procedures running on the network, locking of the aforementioned files and records, through which a portion of a file can be defined and made accessible to only one user at a time, preventing sharing conflicts of installed disks on the server. By means of Dos version 3.1 and the subsequent version, the user transparently handles disks and remote devices, working as if these were connected to his personal workstation. The NetWare Novell solution has started to take care of local networks starting in 1981 and, since then, has developed a decidedly different approach to the problem, from the one adopted by Microsoft. Its network software, NetWare, does not use the Smb, but makes use of a particular high-efficiency protocol called NetWare file services protocol (NFSP) . The functions of Redirector and of NetBIOS and are grouped together in a single emulation module, while Dos is fully bypassed by creating a direct relationship between NetWare and the hardware. The nodes connected to the network applications work with Ms Dos while interacting with NetWare in a transparent manner so that the network software solves all coexistence problems with Microsoft Dos. In the following articles, we will examine the benefits and disadvantages of each of these approaches.